A US woman who shot and killed her husband and two adult children before taking her own life is thought to have committed the shocking crime as a result of being ostracised from the religion she was raised in.

A federal judge sentenced a former Arkansas judge Wednesday to five years in prison — a stiffer punishment than prosecutors recommended — after he admitted giving young male defendants lighter sentences in return for personal benefits that included sexual favours.

Every time I tell a mate I’m doing a story on cryptocurrency, they invariably ask me the same two questions: should they invest their own hard-earned money, and which cryptocurrency will get them a Lamborghini/yacht/island quickest?

In a 60 Minutes online exclusive, reporter Liz Hayes quizzed Australian Prime Minister Malcolm Turnbull on his relationship with the unpredictable Twitter aficionado and US president Donald Trump ahead of their meeting at the White House Friday.

WA Christmas shoppers to spend $5b

West Australians are expected to spend more than $5 billion in the lead-up to Christmas, on par with last year's festive spending.

Australian Retailers Association executive director Russell Zimmerman said there was no increase from last year as there was pressure on food pricing in the state from the roll out of Aldi stores.

"Food sales make up 40 per cent of retail figures," he told AAP on Friday.

"Coles and Woolworths want to keep their market share so there's pressure on food prices.

"Fortunately for consumers, there's not much growth in retail while food is under pressure."

The national average for Christmas spending increased by 2.3 per cent, with shoppers forecast to spend a total of $48.1 billion in the six weeks leading to Christmas, $19.4 billion of which will have been on food.

The Northern Territory is the only other state where holiday spending did not increase, however WA residents are expected to embrace the post-Christmas sales.